Diastereoselective Ugi reaction without chiral amines: the synthesis of chiral pyrroloketopiperazines
作者:Valentine G. Nenajdenko、Alexander L. Reznichenko、Elizabeth S. Balenkova
DOI:10.1016/j.tet.2007.01.056
日期:2007.4
The three-component Ugireaction with chiral 2-(2-formyl-1H-pyrrol-1-yl)acetic acids prepared from natural l-aminoacids was investigated. The reaction opens a new route to chiral substituted pyrroloketopiperazines. One of the first examples of an asymmetric Ugireaction without chiral amines is described. The reaction proceeds with moderate diastereoselectivity to give the target compounds in good
2-(5-Hydroxymethyl-2-formylpyrrol-1-yl)propionic acid lactone was synthesized in six steps with a 17.0% overall yield, starting from L-alanine. The synthetic route involved the Clauson-Kaas reaction, Vilsmeier reaction, and transesterification. The transesterification was the key step in the formation of the target compound.